Some features of epoxidation of cyclohexene catalyzed by oxoperoxometallates under phase-transfer conditions

Csányi, László J.; Jáky, Károly

doi:10.1016/0021-9517(91)90207-k

Cited by 40 publications

(9 citation statements)

References 18 publications

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“…This type of W catalyst was found to use H 2 O 2 more efficiently than many other oxidation catalysts. A related Mo compound (viz., (NMe 4 ) 2 [PhPO 3 {MoO(O 2 ) 2 } 2 (H 2 O)]) was also prepared, and its catalytic ability in epoxidation was examined: it showed that it was much less efficient than the tungsten systems even in harsh reaction conditions. Even the W catalysts exhibited moderate turnovers and low selectivities, and so, the catalyst economy, which is a very important factor, was low.…”

Section: Introductionmentioning

confidence: 99%

Oxo- and Oxoperoxo-molybdenum(VI) Complexes with Aryl Hydroxamates: Synthesis, Structure, and Catalytic Uses in Highly Efficient, Selective, and Ecologically Benign Peroxidic Epoxidation of Olefins

et al. 2006

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A solution obtained by dissolving MoO3 in H2O2 reacts separately with secondary hydroxamic acids (viz., N-benzoyl N-phenyl hydroxamic acid (BPHAH), N-benzoyl N-ortho-, -meta-, -para-tolyl hydroxamic acids, (BOTHAH, BMTHAH, and BPTHAH, respectively), and N-cinnamoyl N-phenyl hydroxamic acid (CPHAH) affording [MoO(O2)(BPHA)2] (1), [MoO(O2)(BOTHA)2] (2), [MoO(O2)(BMTHA)2] (3), [MoO(O2)(BPTHA)2] (4), and [Mo(O)2(CPHA)2](5), respectively. The O and O2 are situated cis to each other in 2-4, but in each case, they are disordered and distributed over four sites. This disorder does not exist in the 6-coordinate cis dioxo complex 5, to which crude MoO(O2)(CPHA)2 (5') was converted during recrystallization. An aqueous molybdate solution readily reacts with all those hydroxamic acids producing [Mo(O)2(hydroxamate)2] (6). While 2, 3, and 4 possess a very distorted pentagonal bipyramidal structure, 5 has a distorted octahedral geometry. In the solid state, as well as in solution, 5 exists as two apparently enantiomerically related molecules differing in the orientation of the pendant phenyl rings. To emphasize that the formation and structural uniqueness of 5 compared to 1-4 is caused by the influence of the cinnamoyl residue, one compound of the 6 series, namely, [Mo(O)2(BPHA)2] (6A), was structurally characterized to prove directly that the special stereochemical properties of 5 rely on the special electronic structure of CPHA- ligand. Complexes 1-5, as well as 6, show high potential and selectivity as catalysts in the epoxidation of olefins at room temperature in the presence of NaHCO3 as a promoter and H2O2 as a terminal oxidant. A comparative epoxidation study has been performed to determine the relative efficiency of the catalysts. To make the epoxidation method cost effective, a study to optimize the use of H2O2 has also been performed. To obtain evidence in favor of our suggested mechanism to this homogeneous olefin --> epoxide conversion, it was necessary to synthesize a peroxo-rich compound, namely, [MoO(O2)2BMTHA]- (7), but the attempted synthesis culminated in the isolation of [MoO(O2)2(C6H5COO)]- (8), obviously, via the hydrolysis of coordinated BMTHA.

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Section: Introductionmentioning

confidence: 99%

Oxo- and Oxoperoxo-molybdenum(VI) Complexes with Aryl Hydroxamates: Synthesis, Structure, and Catalytic Uses in Highly Efficient, Selective, and Ecologically Benign Peroxidic Epoxidation of Olefins

et al. 2006

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“…Salts of the anion have been prepared by several groups; [11][12][41][42][43] despite many attempts to show that 1, 2 and 6 are isomorphous, it was previously difficult to isolate single crystals of 6 suitable for X-ray measurements. The profiles of the Raman and infrared spectra of 6 are compared with those of tetran-butylammonium (µ-hydrogenoarsenato)bis(µ-peroxo)bis-(oxoperoxotungstate)(2-) (4) [14] and with those of the methylarsenato analogue (5).…”

Section: Introductionmentioning

confidence: 99%

Another Example of the Instability of a Keggin‐Type Heteropolyanion in the Presence of Aqueous Hydrogen Peroxide: From [AsW₁₂O₄₀]^3– to Low‐Nuclearity Oxoperoxotungstates – Crystal Structure of [(nHex)₄N]₃[AsO₄{W₂O₂(μ‐O₂)₂(O₂)₂}₂]

et al. 2006

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“…They react to provide industrially important products such as pharmaceuticals, surfactants, detergents, antistatic agents, corrosion protection agents, and additives for laundry detergents, lubricating oils, textiles and cosmetics 10. Few epoxidation processes are carried out in aqueous solution, and most of them need a catalyst and phase transfer agents11–15 or, alternatively, an electrochemical process 16. A method using aqueous potassium peroxymonosulfate (Oxone ® ) solution to oxidize alkenes into epoxides and diols without phase transfer catalyst was investigated by Zhu and Ford 17.…”

Section: Introductionmentioning

confidence: 99%

“…Table 1 summarizes the literature on epoxidation of cyclohexene and cyclooctene by various synthetic processes 11, 14, 15, 17–23. It can be seen that using Oxone ® as the oxidant to produce cyclohexene and cyclooctene oxide is particularly suited for investigating water‐based synthesis of epoxides.…”

Section: Introductionmentioning

confidence: 99%

Two‐phase production of cyclohexene and cyclooctene oxides in water as an approach to pollution prevention

Shu

2004

J of Chemical Tech & Biotech

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Liquid-liquid two-phase epoxidation from cyclohexene and cyclooctene in aqueous potassium peroxymonosulfate (commercially available as Oxone  ) solution was studied as an application in pollution prevention. To avoid potential emissions of volatile organic compounds an aqueous solution was employed to replace the usual chlorinated solvents used in epoxide production. A droplet column reactor and stirred tank reactor were used to investigate two-phase synthesis of epoxide. An aqueous Oxone  solution was used to oxidize a dispersion of alkene droplets and form epoxide. The study of aqueous epoxidation in both reactors showed that the epoxidation of alkenes can be represented as a first order reaction with respect to alkene. The salting out effect of Oxone  concentration was studied in both reactors and found to be very similar at optimal conditions. In comparing the two reactors, it was found that the droplet column reactor produces larger quantities of product per unit reactor volume for the same reaction time. The objective of this study is to provide an alternative reactor design and synthesis route that can meet pollution prevention goals.

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Some features of epoxidation of cyclohexene catalyzed by oxoperoxometallates under phase-transfer conditions

Cited by 40 publications

References 18 publications

Oxo- and Oxoperoxo-molybdenum(VI) Complexes with Aryl Hydroxamates: Synthesis, Structure, and Catalytic Uses in Highly Efficient, Selective, and Ecologically Benign Peroxidic Epoxidation of Olefins

Oxo- and Oxoperoxo-molybdenum(VI) Complexes with Aryl Hydroxamates: Synthesis, Structure, and Catalytic Uses in Highly Efficient, Selective, and Ecologically Benign Peroxidic Epoxidation of Olefins

Another Example of the Instability of a Keggin‐Type Heteropolyanion in the Presence of Aqueous Hydrogen Peroxide: From [AsW₁₂O₄₀]^3– to Low‐Nuclearity Oxoperoxotungstates – Crystal Structure of [(nHex)₄N]₃[AsO₄{W₂O₂(μ‐O₂)₂(O₂)₂}₂]

Two‐phase production of cyclohexene and cyclooctene oxides in water as an approach to pollution prevention

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Some features of epoxidation of cyclohexene catalyzed by oxoperoxometallates under phase-transfer conditions

Cited by 40 publications

References 18 publications

Oxo- and Oxoperoxo-molybdenum(VI) Complexes with Aryl Hydroxamates: Synthesis, Structure, and Catalytic Uses in Highly Efficient, Selective, and Ecologically Benign Peroxidic Epoxidation of Olefins

Oxo- and Oxoperoxo-molybdenum(VI) Complexes with Aryl Hydroxamates: Synthesis, Structure, and Catalytic Uses in Highly Efficient, Selective, and Ecologically Benign Peroxidic Epoxidation of Olefins

Another Example of the Instability of a Keggin‐Type Heteropolyanion in the Presence of Aqueous Hydrogen Peroxide: From [AsW12O40]3– to Low‐Nuclearity Oxoperoxotungstates – Crystal Structure of [(nHex)4N]3[AsO4{W2O2(μ‐O2)2(O2)2}2]

Two‐phase production of cyclohexene and cyclooctene oxides in water as an approach to pollution prevention

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Another Example of the Instability of a Keggin‐Type Heteropolyanion in the Presence of Aqueous Hydrogen Peroxide: From [AsW₁₂O₄₀]^3– to Low‐Nuclearity Oxoperoxotungstates – Crystal Structure of [(nHex)₄N]₃[AsO₄{W₂O₂(μ‐O₂)₂(O₂)₂}₂]